Federal Register / Vol. 76, No. 75 / Tuesday, April 19, 2011 / Proposed Rules 21815 

environmental impact statement is 

required. 

II. Approval of the Office of the 

Secretary 

The Secretary of Energy has approved 

publication of today’s NOPR. 

List of Subjects in 10 CFR Part 429 

Confidential business information, 

Energy conservation, Household 

appliances, Imports, Reporting and 

recordkeeping requirements. 

Issued in Washington, DC, on April 12, 

2011. 

Kathleen Hogan, 

Deputy Assistant Secretary for Energy 

Efficiency, Office of Technology 

Development, Energy Efficiency and 

Renewable Energy. 

For the reasons stated in the 

preamble, DOE is proposing to amend 

part 429 of title 10 of the Code of 

Federal Regulations, as set forth below: 

PART 429—CERTIFICATION, 

COMPLIANCE, AND ENFORCEMENT 

FOR CONSUMER PRODUCTS AND 

COMMERCIAL AND INDUSTRIAL 

EQUIPMENT 

1. The authority citation for part 429 

continues to read as follows: 

Authority: 42 U.S.C. 6291–6317. 

2. Add in § 429.12 a new paragraph (i) 

to read as follows: 

§ 429.12 General requirements applicable 

to certification reports. 

* * * * * 

(i) Certain commercial equipment. 

Manufacturers of commercial 

refrigeration equipment; commercial 

heating, ventilating, air-conditioning 

(HVAC) equipment; commercial water 

heating equipment; walk-in coolers; 

walk-in freezers; and automatic 

commercial ice makers are not required 

to comply with paragraphs (a) through 

(f) of this section until [date 18 months 

following publication of final rule]. 

[FR Doc. 2011–9473 Filed 4–18–11; 8:45 am] 

BILLING CODE 6450–01–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0415; Directorate 

Identifier 2007–NM–256–AD] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Model 737 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Supplemental notice of 

proposed rulemaking (NPRM); 

reopening of comment period. 

SUMMARY: We are revising an earlier 

proposed airworthiness directive (AD) 

for certain Model 737 airplanes. The 

original NPRM would have required 

repetitive inspections, lubrications, and 

repetitive repairs/overhauls of the ball 

nut and ballscrew and attachment 

(Gimbal) fittings for the trim actuator of 

the horizontal stabilizer; various 

installation(s); and corrective actions if 

necessary; as applicable. The original 

NPRM resulted from a report of 

extensive corrosion of a ballscrew used 

in the drive mechanism of the 

horizontal stabilizer trim actuator 

(HSTA). This action revises the original 

NPRM by adding airplanes to the 

applicability. We are proposing this 

supplemental NPRM to prevent an 

undetected failure of the primary load 

path for the ballscrew in the drive 

mechanism of the HSTA and 

subsequent wear and failure of the 

secondary load path, which could lead 

to loss of control of the horizontal 

stabilizer and consequent loss of control 

of the airplane. 

DATES: We must receive comments on 

this supplemental NPRM by May 16, 

2011. 

ADDRESSES: You may send comments by 

any of the following methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue, SE., Washington, DC 20590. 

• Hand Delivery: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue, SE., Washington, DC 20590, 

between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

For service information identified in 

this proposed AD, contact Boeing 

Commercial Airplanes, Attention: Data 

& Services Management, P.O. Box 3707, 

MC 2H–65, Seattle, Washington 98124– 

2207; telephone 206–544–5000, 

extension 1, fax 206–766–5680; e-mail 

me.boecom@boeing.com; Internet 

https://www.myboeingfleet.com. You 

may review copies of the referenced 

service information at the FAA, 

Transport Airplane Directorate, 1601 

Lind Avenue, SW., Renton, Washington. 

For information on the availability of 

this material at the FAA, call 425–227– 

1221. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http:// 

www.regulations.gov; or in person at the 

Docket Management Facility between 

9 a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. The AD 

docket contains this proposed AD, the 

regulatory evaluation, any comments 

received, and other information. The 

street address for the Docket Office 

(telephone 800–647–5527) is in the 

ADDRESSES section. Comments will be 

available in the AD docket shortly after 

receipt. 

FOR FURTHER INFORMATION CONTACT: 

Kelly McGuckin, Aerospace Engineer, 

Systems and Equipment Branch, ANM– 

130S, FAA, Seattle Aircraft Certification 

Office, 1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone 

(425) 917–6490; fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to send any written 

relevant data, views, or arguments about 

this proposed AD. Send your comments 

to an address listed under the 

ADDRESSES section. Include ‘‘Docket No. 

FAA–2008–0415; Directorate Identifier 

2007–NM–256–AD’’ at the beginning of 

your comments. We specifically invite 

comments on the overall regulatory, 

economic, environmental, and energy 

aspects of this proposed AD. We will 

consider all comments received by the 

closing date and may amend this 

proposed AD because of those 

comments. 

We will post all comments we 

receive, without change, to http:// 

www.regulations.gov, including any 

personal information you provide. We 

will also post a report summarizing each 

substantive verbal contact we receive 

about this proposed AD. 

Discussion 

We issued a notice of proposed 

rulemaking (NPRM) (the ‘‘original 

NPRM’’) to amend 14 CFR part 39 to 

include an airworthiness directive (AD) 

that would apply to certain Boeing 

Model 737 airplanes. That original 

NPRM was published in the Federal 

Register on April 28, 2008 (73 FR 

22840). That original NPRM proposed to 

require repetitive inspections, 

lubrications, and repetitive repairs/ 

overhauls of the ball nut and ballscrew 

and attachment (Gimbal) fittings for the 

trim actuator of the horizontal stabilizer; 

various installation(s); and corrective 

actions if necessary; as applicable. 

That original NPRM resulted from a 

report of extensive corrosion of a 

ballscrew used in the drive mechanism 


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of the horizontal stabilizer trim actuator 

(HSTA) on a Model 757 airplane. 

Extensive corrosion of the primary load 

path ball bearings in the ballscrew 

assembly, if not corrected, could result 

in an undetected failure of the primary 

load path for the ballscrew in the drive 

mechanism of the HSTA and 

subsequent wear and failure of the 

secondary load path, which could lead 

to loss of control of the horizontal 

stabilizer and consequent loss of control 

of the airplane. 

The ballscrew assembly on Model 757 

airplanes is similar to those on the 

affected Model 737 airplanes. Therefore, 

all of these models may be subject to the 

same unsafe condition. 

Other Relevant Rulemaking 

We are considering additional 

rulemaking to address the identified 

unsafe condition on Model 757 

airplanes. 

Relevant Service Information 

We have reviewed Boeing Alert 

Service Bulletins 737–27A1277, 

Revision 2, dated January 8, 2010 (for 

Model 737–600, –700, –700C, –800, 

–900, and –900ER series airplanes); and 

737–27A1278, Revision 1, dated January 

7, 2010 (for Model 737–100, –200, 

–200C, –300, –400, and –500 series 

airplanes). Boeing Alert Service 

Bulletins 737–27A1277, Revision 1, 

dated July 25, 2007; and 737–27A1278, 

dated May 24, 2007; were referred to in 

the original NPRM as the appropriate 

sources of service information for 

accomplishing the proposed actions. 

The revisions of the service information 

incorporate the following changes: 

• Boeing Alert Service Bulletin 737– 

27A1277, Revision 2, dated January 8, 

2010, adds Model 737–900ER airplanes 

to Group 2 of the effectivity, clarifies 

certain inspections necessary in Work 

Packages 1 and 2, and contains certain 

editorial changes. 

• Boeing Alert Service Bulletin 737– 

27A1278, Revision 1, dated January 7, 

2010, corrects the work instructions for 

the horizontal stabilizer trim actuator 

(HSTA) name plate identification 

information in Work Package 4 and 

clarifies certain inspections necessary in 

Work Packages 1 and 2 and contains 

certain editorial changes. In addition, 

the Horizontal Stabilizer Gearbox End 

Play Test is added because the gearbox 

backlash inspection is only identified in 

the airplane maintenance manual for 

Model 737–600, –700, –800, and –900 

airplanes, but is also applicable to 

Model 737–100, –200, –300, –400, and 

–500 airplanes. 

Actions Since Issuance of Original 

NPRM 

Since we issued the original NPRM, 

we have changed this supplemental 

NPRM to include the revised service 

information, which expands the 

applicability of the original NPRM. We 

have also revised paragraph (h) of the 

original NPRM (paragraph (g) of the 

supplemental NPRM) to include credit 

for actions accomplished before the 

effective date of the AD in accordance 

with previous revisions of the service 

information. 

Comments 

We have considered the following 

comments on the original NPRM. 

Request To Change Applicability 

Boeing asked that we revise the 

applicability in the original NPRM to 

specify that it applies to all Model 737 

airplanes instead of listing the minor 

models associated with the referenced 

service information. Boeing stated that 

this would avoid possible supersedure 

of the AD or certification maintenance 

requirements on future type certification 

programs. 

We agree with the commenter for the 

reasons provided. We have changed 

paragraph (c) and the SUMMARY section 

of this supplemental NPRM to refer to 

all Model 737 airplanes. 

Request To Clarify Procedures in 

Referenced Service Information 

Air Transport Association (ATA), on 

behalf of its member Air Tran Airways 

(Air Tran) stated that the referenced 

service information is very difficult to 

interpret and cites examples from the 

service information. Air Tran stated that 

the accomplishment instructions 

specified in the service information 

contain language that is not specific and 

can not be used to make definitive 

determinations with regard to 

serviceability. Air Tran cited an 

example in Section 3.B.1.d.(2) of Boeing 

Alert Service Bulletin 737–27A1277, 

Revision 1, dated July 25, 2007, which 

specifies ‘‘Large amounts of grease 

present * * *’’. This language is not 

specific and open to a high degree of 

subjectivity. Air Tran added that other 

examples are in Section 3.B.1.n.(1) of 

this service bulletin, which specifies 

‘‘majority of grease,’’ and in several 

places in Figures 1 and 2 of this service 

bulletin. Air Tran notes that the work 

instructions in Section 3.B. of Boeing 

Alert Service Bulletin 737–27A1277, 

Revision 1, dated July 25, 2007, do not 

exactly match the instructions provided 

with the figures. Air Tran stated that 

having two sets of work instructions 

makes if difficult to follow, and could 

result in missed or partially 

accomplished work steps. Air Tran adds 

that Section 3.B.1.d.(8)(c) of this service 

bulletin provides instructions to check 

for obvious differences in thread shape 

between thread grooves ‘‘as given in 

CMM 27–41–01.’’ Air Tran noted that 

CMM 27–41–01 does not provide any 

procedure for checking for obvious 

differences. Air Tran also noted that the 

subject section should specify ‘‘refer to’’ 

rather than ‘‘as given in.’’ 

Qantas has similar views to Air Tran 

and added that referring to the 

procedures specified by Air Tran for the 

on-wing inspection will be confusing to 

mechanics because the procedures are 

not designed to be completed on-wing. 

Qantas also suggested a better 

explanation and pictures be added to 

Section 3.B.1.n.(1) of Boeing Alert 

Service Bulletin 737–27A1277, Revision 

1, dated July 25, 2007, to quantify what 

is normal and what is an indication of 

a failure. Qantas noted that where there 

is evidence of a grease seal starting to 

fail, but no metallic debris, replacement 

of the unit should be deferred for up to 

five days, this would ease the burden of 

excess airplane down time. Qantas also 

noted that Section 3.B.1(o) of the 

procedures is not specified in the 

requirement table in paragraph 1.E. of 

Boeing Alert Service Bulletin 737– 

27A1277, Revision 1, dated July 25, 

2007. Qantas suggested it be included in 

that paragraph. Qantas also asks that the 

detailed inspection criteria specified in 

Section 3.B.1.(d) of this service bulletin 

be clarified. 

We agree that the procedures in the 

referenced service information should 

be clarified. We asked Boeing to revise 

the subject service information to 

provide better guidance and further 

clarification of the tasks that are 

specified. Boeing revised the service 

information as requested, as noted 

under the ‘‘Actions Since Original 

NPRM was Issued’’ and ‘‘Relevant 

Service Information,’’ sections of this 

AD and further clarification of the 

procedures is provided in those 

revisions, as well as the deletion of 

unnecessary procedures. Some portions 

of the task descriptions were left open 

to allow operators some latitude in 

accomplishing the tasks. We have 

revised this AD to refer to the new 

service information. 

We agree that processes referred to by 

the commenters are not designed for onwing or on-airplane inspections. Boeing 

provides clarification of the intent of 

these processes in Boeing Alert Service 

Bulletin 737–27A1277, Revision 2, 

dated January 8, 2010. Therefore, we 

have made no change to the 


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supplemental NPRM regarding this 

issue. 

Qantas also asked that Boeing Alert 

Service Bulletin 737–27A1277, Revision 

1, dated July 25, 2007, be revised. 

Qantas stated that the footnote at the top 

of page 10 of that service bulletin 

specifies ‘‘Boeing recommends that 

operators continue to perform 

lubrication tasks for the Stabilizer Trim 

Actuator given in Maintenance Planning 

Document (MPD) Section 1 and 737 

AMM 12–22–41.’’ Qantas added that the 

MPD task requires lubrication every 

1,600 flight hours or 8 months, and 

paragraph 3.B.1., of Boeing Alert Service 

Bulletin 737–27A1277, Revision 1, 

dated July 25, 2007, specifies doing the 

same task every 1,600 flight hours or 12 

months. Qantas noted that the Boeing 

737 MPD and service bulletin tasks 

should not both be required. Qantas 

stated that the FAA or Boeing should 

clarify the lubrication tasks specified in 

that service bulletin, so operators can 

take credit for doing the task in 

accordance with that service bulletin. 

We agree with the commenter. Boeing 

revised the service information 

specified in the ‘‘Relevant Service 

Information’’ and ‘‘Actions Since 

Original NPRM was Issued’’ sections of 

this supplemental NPRM. The 

referenced note has been removed and 

a new note added to Table 1 of 

paragraph 1.E., Compliance, of both 

service bulletins, specifying that 

accomplishing the lubrication task in 

Boeing Alert Service Bulletin 737– 

27A1277 or 737–27A1278 meets the 

intent of the lubrication task in the 

associated MPD. 

Clarify Difference in Compliance Time 

Intervals 

Boeing and US Airways asked that the 

compliance time interval specified in 

the original NPRM for the repetitive 

repair/overhaul be changed from 20,000 

or 25,000 flight cycles to 20,000 or 

24,000 flight hours (depending on 

airplane configuration) for Model 737– 

100, –200, –300, –400, and –500 series 

airplanes. Boeing stated that Tables 1 

and 2 of Boeing Alert Service Bulletin 

737–27A1278, dated May 24, 2007, 

specify the correct interval. Boeing adds 

that the subsection, Repetitive Repair/ 

Overhaul, should be changed from ‘‘and 

thereafter at intervals not to exceed 

20,000 or 25,000 flight cycles * * *’’ to 

‘‘and thereafter at intervals not to exceed 

20,000 or 24,000 flight hours * * *’’ US 

Airways reiterated the Boeing comment 

and recommends the difference be 

clarified. 

We agree that clarification is 

necessary. The repetitive interval 

referred to in the original NPRM is 

incorrect. The correct interval of 20,000 

flight hours or 24,000 flight hours 

(depending on airplane configuration) is 

specified in Boeing Alert Service 

Bulletin 737–27A1278, Revision 1, 

dated January 7, 2010. We have clarified 

the compliance time in this 

supplemental NPRM by referring to 

Boeing Alert Service Bulletin 737– 

27A1278, Revision 1, dated January 7, 

2010. 

Clarify Difference in Secondary Service 

Information Reference 

US Airways asked that the secondary 

service information referenced in Note 1 

of the original NPRM be clarified. US 

Airways stated that Note 1 refers to 

Linear Motion Service Bulletin 7901708, 

Revision A, dated July 26, 2005; 

however, the service bulletin supplied 

to US Airways from Linear Motion 

specifies Revision B. 

We agree with the commenter. Since 

Revision B merely corrects a 

typographical error, Linear Motion 

Service Bulletin 7901708, Revisions A 

and B, both dated July 26, 2005, are 

acceptable. We have revised Note 1 of 

this supplemental NPRM accordingly. 

Request for Credit for Accomplishing 

Previously Issued Service Information 

US Airways referenced paragraph (h) 

of the original NPRM which specified 

‘‘Actions done before the effective date 

of this AD in accordance with Boeing 

Alert Service Bulletin 737–27A1277, 

dated July 21, 2005, are acceptable for 

compliance with the corresponding 

requirements of this AD.’’ US Airways 

asked that a similar paragraph be added 

to give credit for previous 

accomplishment of Boeing Alert Service 

Bulletin 737–27A1278, dated May 24, 

2007. 

We agree with the commenter and 

have changed paragraph (g) of this 

supplemental NPRM to give credit for 

certain actions done in accordance with 

Boeing Alert Service Bulletin 737– 

27A1278, dated May 24, 2007. 

Request To Clarify Compliance Times 

Boeing asked that an additional 

statement be added to the compliance 

time in paragraph (g) of the original 

NPRM to clarify that it is dependent on 

the airplane configuration defined in the 

referenced service information. Boeing 

stated that the multiple recommended 

compliance times may be confusing to 

operators as there is no distinction of 

dependence on airplane configuration 

for the initial compliance times. Boeing 

suggested clarifying the compliance 

time by adding ‘‘(depending upon 

airplane configuration called out in the 

SB)’’ in parenthesis. 

We agree with the commenter for the 

reasons provided. We have changed 

paragraph (g) of the supplemental 

NPRM to include the phrase ‘‘depending 

on airplane configuration’’ in 

parenthesis following the compliance 

time reference. 

Request To Use Continuous 

Maintenance Program/Move 

Maintenance Planning Document 

(MPD) Tasks to Referenced Service 

Information 

ATA on behalf of its member 

American Airlines reiterated the 

American Airlines comment that, except 

for accomplishing the installation of the 

strengthened ballnut retainers, all 

remaining requirements are part of the 

Model 737–800 continuous 

maintenance program and are subject to 

the type certification maintenance 

program rules. American Airlines stated 

that there are no historical indications 

for Model 737–NG airplanes that 

warrant an AD. American Airlines did 

not agree that the requirements in the 

AD that pertain to different airplane 

models with different designs and 

component manufacturers are strong 

enough to suspend parts of a continuous 

maintenance program. American 

Airlines added that if we have data not 

cited in the NPRM that substantiates an 

AD then the specified tasks should be 

removed from the continuous 

maintenance program. American 

Airlines concluded that continuous 

maintenance tasks such as inspection 

and lubrication typically have no 

terminating action by definition. 

Air Tran supported the requirement to 

accomplish the installation of the 

strengthened ballnut retainers, but also 

requested that we allow the use of 

maintenance tasks and states that the 

lubrication requirements of Boeing Alert 

Service Bulletin 737–27A1277, Revision 

1, dated July 25, 2007, are similar to 

those in Boeing 737NG MPD Task 27– 

102–00 and the inspection requirements 

are similar to those in Boeing 737NG 

MPD Task 27–110–00. Air Tran added 

that the full requirements of Boeing 

737NG MPD Tasks 27–102–00 and 27– 

110–00 should be incorporated into the 

AD and the subject MPD tasks removed 

from the Boeing 737NG MPD to avoid 

confusion. Qantas also asked that 

Boeing 737NG MPD Task 27–110–00–1 

be incorporated into Boeing Alert 

Service Bulletin 737–27A1277, Revision 

1, dated July 25, 2007. Qantas stated 

that if this task is included operators 

will not perform duplicate tasks from 

the Boeing 737NG MPD and referenced 

service information. 

We infer that ATA, American 

Airlines, Air Tran, and Qantas are 


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asking that the Boeing 737NG MPD 

Tasks specified in the original NPRM be 

removed, except for accomplishing the 

installation of the strengthened ballnut 

retainers, because all remaining 

requirements are part of the 

maintenance program. We do not agree 

with the commenters. We proposed 

mandating the maintenance tasks and 

intervals because of the criticality of 

maintaining the horizontal stabilizer 

control system; the consequences of not 

performing the maintenance tasks; and 

the service history attributed to lack of 

adequate horizontal stabilizer system 

maintenance on other airplanes. These 

maintenance actions can affect the 

safety of the airplane if they are not 

performed in a timely manner. We 

approve the maintenance review board 

report (MRBR), which is the basis for 

the MPD; the MRBR is an industry 

document that can only be changed by 

the MRB. The overlap is noted in Boeing 

Alert Service Bulletin 737–27A1277, 

Revision 1, dated July 25, 2007, which 

identifies the MPD tasks. No revision to 

the MRBR is currently planned. Failure 

to perform the actions in this 

supplemental NPRM can lead to an 

unsafe condition; therefore, we have 

made no change to the supplemental 

NPRM in this regard. 

Sun Country Airlines (Sun Country) 

stated that operators may need 

clarification on whether or not ‘‘restore,’’ 

as identified in Boeing 737NG MPD 

Item 27–108–00, meets the intent of the 

actions in the original NPRM. Sun 

Country stated that the repetitive 

actions specified in Boeing Alert Service 

Bulletin 737–27A1277, Revision 1, 

dated July 25, 2007, are closely related 

to Boeing 737NG MPD Items 27–102–00, 

27–108–00, and 27–110–00, in 

procedure as well as interval. Sun 

Country asked if operators following 

these MPD items can take credit for 

those already established maintenance 

requirements in lieu of the actions in 

the original NPRM. Sun Country added 

that because these MPD items already 

exist it would be advisable to change 

them to certification maintenance 

requirements (CMR) instead of 

mandating AD action. 

We agree that certain requirements in 

Boeing Alert Service Bulletin 737– 

27A1277, Revision 1, dated July 25, 

2007, are similar to those tasks in the 

Boeing 737NG MPD. Boeing revised the 

referenced service information to 

address this issue. A note was added to 

the compliance tables in the service 

information stating that accomplishing 

the lubrication task in the service 

information meets the intent of Boeing 

737NG MPD lubrication Task 27–102– 

00. We do not agree that the MPD Items 

should be changed to CMR 

requirements, because CMR 

requirements are established as part of 

the type certification of an airplane and 

are not initiated due to in-service issues. 

There are certain differences between 

the MPD tasks and the proposed 

requirements in the supplemental 

NPRM (e.g., inspections of the cable 

drum and electrical connector are not 

part of the actions specified in the 

referenced service information). We 

have made no change to the 

supplemental NPRM in this regard. 

Request To Include Serial Numbers for 

Ballnut Tube Retainer Units 

ATA on behalf of its member Air Tran 

noted that the identification of multiple 

airplane groups creates some confusion 

regarding which ballnut tube retainer 

units need to be installed. Air Tran 

asked that the AD identify the specific 

serial numbers of the units requiring 

modification to ensure that all affected 

units are covered. 

We do not agree with the commenters. 

Operators can determine if the 

modification has been incorporated by 

verifying the part number on the 

component or doing a visual inspection 

of the ballscrew assembly. The proposed 

requirements in this supplemental 

NPRM prohibit the installation of 

affected unmodified ballscrews on 

certain airplanes. As standard practice, 

the airplane manufacturer addresses 

affected airplanes in the delivered 

condition in the effectivity of its service 

information. We have made no change 

to the supplemental NPRM in this 

regard. 

Request To Review Paragraph 1.E. of 

the Referenced Service Information 

Qantas asked that we review whether 

the desired level of inspection will be 

achieved using the current Boeing 737 

CMM. Qantas stated that paragraph 1.E. 

of Boeing Alert Service Bulletin 737– 

27A1277, Revision 1, dated July 25, 

2007, specifies an overhaul every 25,000 

flight hours; Boeing 737 CMM 27–45–12 

recommends the unit to be tested and 

disassembled only to the extent 

necessary to repair test failures. Qantas 

required vendors to strip the unit and 

complete visual and magnetic particle 

inspections. 

We do not agree with the commenter. 

The intervals and tasks necessary for the 

lubrication, detailed inspection and 

overhaul/repair of the HSTA described 

in Boeing Alert Service Bulletin 737– 

27A1277, Revision 2, dated January 8, 

2010, and proposed in this 

supplemental NPRM, address the unsafe 

condition of an undetected failure of the 

ballscrew primary load path and 

subsequent wear and failure of the 

secondary load path for affected 

airplanes. Due to these factors, we have 

determined that the desired level of 

inspection will be achieved when 

performing an HSTA overhaul. We have 

made no change to the supplemental 

NPRM in this regard. 

Request To Extend Overhaul Life Limit 

Qantas stated that by making the 

overhaul life limit mandatory the airline 

loses any flexibility in escalating the 

overhaul life based on service 

experience. Qantas added that there is 

considerable safety benefit in doing 

thorough overhauls with feedback of 

findings; one of the incentives for doing 

this is it includes the possibility of an 

overhaul life extension. Qantas noted 

that the original NPRM indicates an 

overhaul cost of $3,200; however, a 

recent procurement exercise by Qantas 

indicated the overhaul costs are about 

$18,000 per unit, not including any 

parts replacements. Qantas concluded 

that there is a considerable burden if 

extending the overhaul life is not 

permitted. 

We do not agree to extend the 

intervals for maintenance tasks based on 

the commenter’s service experience. In 

consideration of the safety implications, 

we determined that the compliance time 

for the maintenance tasks, as proposed, 

represents an appropriate interval in 

which the overhaul can be done in a 

timely manner within the fleet, while 

still maintaining an adequate level of 

safety. Although we acknowledge that 

the overhaul cost may be higher, the 

estimate in this supplemental NPRM is 

limited only to the cost of actions 

actually required by the AD, and is 

based on an estimate from the airplane 

manufacturer of the labor hours and 

subsequent cost necessary to 

accomplish those tasks. Therefore, we 

have made no change to the 

supplemental NPRM is this regard. 

FAA’s Determination and Proposed 

Requirements of the Supplemental 

NPRM 

We are proposing this supplemental 

NPRM because we evaluated all 

pertinent information and determined 

an unsafe condition exists and is likely 

to exist or develop on other products of 

the same type design. Certain changes 

described above expand the scope of the 

original NPRM. As a result, we have 

determined that it is necessary to reopen 

the comment period to provide 

additional opportunity for the public to 

comment on this supplemental NPRM. 


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Explanation of Changes to This 

Supplemental NPRM 

We have added a new paragraph (d) 

to this supplemental NPRM to provide 

the Air Transport Association (ATA) of 

America subject code 27; flight controls. 

This code is added to make this 

supplemental NPRM parallel with other 

new AD actions. We have reidentified 

subsequent paragraphs accordingly. 

We have removed Table 1 of the 

NPRM from this supplemental NPRM. 

Instead, we have provided the full 

service bulletin citations throughout 

this supplemental NPRM. 

Since issuance of the original NPRM, 

we have increased the labor rate used in 

the Costs of Compliance from $80 per 

work-hour to $85 per work-hour. The 

Costs of Compliance information, 

below, reflects this increase in the 

specified hourly labor rate. 

Costs of Compliance 

We estimate that this proposed AD 

would affect 1,641 airplanes of U.S. 

registry. The following table provides 

the estimated costs for U.S. operators to 

comply with this proposed AD. 

ESTIMATED COSTS

Action 1 Work hours 1 Average labor 

rate per hour Parts Cost per product 1

Number of 

U.S.-registered 

airplanes 

Fleet cost 1

Detailed inspections .... 2 or 4 ..................... $85 None ........ $170 or $340, per inspection cycle.1,641 Between $278,970, 

and $557,940 per inspection cycle. 

Lubrications ................. 1 or 3 ..................... 85 None ........ $85 or $255, per lubrication cycle.1,641 Between $139,485, 

and $418,455 per lubrication cycle. 

Repairs/overhauls ....... 40 ........................... 85 None ........ $3,400 per repair/overhaul.1,641 $5,579,400 per repair/ 

overhaul cycle. 

Installations ................. Between 1 and 3 ... 85 $2,200 ..... Between $2,285 and 

$2,455.

1,352 Between $3,089,320 

and $3,319,160. 

1 Depending on airplane configuration. 

The number of work hours, as 

indicated above, is presented as if the 

accomplishment of the actions in this 

proposed AD is to be conducted as new 

‘‘stand alone’’ actions. However, in 

actual practice, the lubrications, 

detailed inspections, and overhauls are 

currently being done as part of normal 

airplane maintenance. The repair can be 

done coincidentally or in combination 

with the normally scheduled HSTA and 

ballscrew overhaul. Therefore, the 

actual number of necessary additional 

work hours will be minimal in many 

instances. Additionally, any costs 

associated with special airplane 

scheduling will be minimal. 

We estimate the following costs to do 

any necessary repairs/replacements that 

would be required based on the results 

of the proposed inspection. We have no 

way of determining the number of 

aircraft that might need these repairs/ 

replacements: 

ON-CONDITION COSTS

Action Labor cost Parts cost Cost per product 

Remove/replace HSTA ............................. Between 3 and 8 work hours × $85 per 

hour = between $255 and $680.

$0 Between $418,455 and $1,115,880. 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. ‘‘Subtitle VII: 

Aviation Programs,’’ describes in more 

detail the scope of the Agency’s 

authority. 

We are issuing this rulemaking under 

the authority described in ‘‘Subtitle VII, 

Part A, Subpart III, Section 44701: 

General requirements.’’ Under that 

section, Congress charges the FAA with 

promoting safe flight of civil aircraft in 

air commerce by prescribing regulations 

for practices, methods, and procedures 

the Administrator finds necessary for 

safety in air commerce. This regulation 

is within the scope of that authority 

because it addresses an unsafe condition 

that is likely to exist or develop on 

products identified in this rulemaking 

action. 

Regulatory Findings 

We determined that this proposed AD 

would not have federalism implications 

under Executive Order 13132. This 

proposed AD would not have a 

substantial direct effect on the States, on 

the relationship between the national 

Government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify this proposed regulation: 

1. Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

2. Is not a ‘‘significant rule’’ under the 

DOT Regulatory Policies and Procedures 

(44 FR 11034, February 26, 1979), and 

3. Will not have a significant 

economic impact, positive or negative, 

on a substantial number of small entities 

under the criteria of the Regulatory 

Flexibility Act. 

You can find our regulatory 

evaluation and the estimated costs of 

compliance in the AD Docket. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 14 CFR part 

39 as follows: 


jdjones on DSK8KYBLC1PROD with PROPOSALS-1
21820 Federal Register / Vol. 76, No. 75 / Tuesday, April 19, 2011 / Proposed Rules 

PART 39—AIRWORTHINESS 

DIRECTIVES 

1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

2. The FAA amends § 39.13 by adding 

the following new AD: 

The Boeing Company: Docket No. FAA– 

2008–0415; Directorate Identifier 2007– 

NM–256–AD. 

Comments Due Date 

(a) We must receive comments by May 16, 

2011. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to all Model 737 

airplanes; certificated in any category. 

Subject 

(d) Air Transport Association (ATA) of 

America Code 27: Flight controls. 

Unsafe Condition 

(e) This AD results from a report of 

extensive corrosion of a ballscrew in the 

drive mechanism of the horizontal stabilizer 

trim actuator (HSTA). We are issuing this AD 

to prevent an undetected failure of the 

primary load path for the ballscrew in the 

drive mechanism of the HSTA and 

subsequent wear and failure of the secondary 

load path, which could lead to loss of control 

of the horizontal stabilizer and consequent 

loss of control of the airplane. 

Compliance 

(f) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Inspections, Lubrications, Repairs/ 

Overhauls, and Applicable Corrective 

Actions 

(g) At the applicable compliance time and 

repeat intervals listed in Tables 1 and 2 of 

paragraph 1.E., ‘‘Compliance,’’ of Boeing Alert 

Service Bulletin 737–27A1278, Revision 1, 

dated January 7, 2010; or Boeing Alert 

Service Bulletin 737–27A1277, Revision 2, 

dated January 8, 2010; as applicable 

(depending on airplane configuration): Do 

the inspections, lubrications, repairs/ 

overhauls, installation(s), and applicable 

corrective actions, by accomplishing all the 

applicable actions specified in the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–27A1278, Revision 1, 

dated January 7, 2010; or Boeing Alert 

Service Bulletin 737–27A1277, Revision 2, 

dated January 8, 2010; as applicable; except 

as provided by paragraphs (g)(1) and (g)(2) of 

this AD. 

Note 1: Boeing Alert Service Bulletin 737– 

27A1278, Revision 1, dated January 7, 2010; 

refers to Umbra Cuscinetti Service Bulletin 

07322–27–01, dated December 21, 2004; 

Linear Motion Service Bulletin 7901708, 

Revision A, or Revision B, both dated July 26, 

2005; Boeing 737 Service Bulletin 27–1046, 

Revision 1, dated April 5, 1974; and 

Skytronics Service Bulletin 93004, dated 

September 1, 2005; as applicable; as 

additional sources of service information for 

accomplishing the applicable specified 

actions. 

Note 2: Boeing Alert Service Bulletin 737– 

27A1277, Revision 2, dated January 8, 2010; 

refers to Umbra Cuscinetti Service Bulletin 

07322–27–01, dated December 21, 2004; as 

an additional source of service information 

for accomplishing the applicable specified 

actions. 

(1) Where paragraph 1.E., ‘‘Compliance,’’ of 

Boeing Alert Service Bulletin 737–27A1278, 

Revision 1, dated January 7, 2010; or Boeing 

Alert Service Bulletin 737–27A1277, 

Revision 2, dated January 8, 2010; as 

applicable; specifies an initial compliance 

time for accomplishing the initial inspection, 

lubrication, or repair/overhaul, this AD 

requires doing the applicable initial action(s) 

at the later of the times specified in 

paragraphs (g)(1)(i) and (g)(1)(ii) of this AD. 

(i) At the applicable compliance time 

specified in paragraph 1.E, ‘‘Compliance,’’ of 

Boeing Alert Service Bulletin 737–27A1278, 

Revision 1, dated January 7, 2010; or Boeing 

Alert Service Bulletin 737–27A1277, 

Revision 2, dated January 8, 2010; as 

applicable. 

(ii) Within the applicable compliance time 

specified in paragraph (g)(1)(ii)(A), 

(g)(1)(ii)(B), or (g)(1)(ii)(C) of this AD. 

(A) For the initial detailed inspection and 

lubrication: Within 6 months after the 

effective date of this AD. 

(B) For the initial repair/overhaul: Within 

12 months after the effective date of this AD. 

(C) For the installation(s): Within 12 

months after the effective date of this AD. 

(2) Where Table 2 of paragraph 1.E., 

‘‘Compliance,’’ of Boeing Alert Service 

Bulletin 737–27A1277, Revision 2, dated 

January 8, 2010, specifies a compliance time 

of ‘‘* * * within 25,000 Flight Hours since 

the latest horizontal stabilizer trim actuator 

(HSTA) Overhaul from the date of Revision 

1 of this Service Bulletin * * *,’’ this AD 

requires compliance within 25,000 flight 

hours since the last overhaul of the trim 

actuator of the horizontal stabilizer. 

Credit for Actions Accomplished in 

Accordance With Previous Service 

Information 

(h) Actions accomplished before the 

effective date of this AD in accordance with 

Boeing Alert Service Bulletins 737–27A1277, 

Revision 1, dated July 25, 2007; or 737– 

27A1278, dated May 24, 2007; as applicable; 

are considered acceptable for compliance 

with the corresponding actions specified in 

this AD. 

Parts Installation 

(i) As of the effective date of this AD, no 

person may install a ballscrew assembly in 

the drive mechanism of the HSTA on any 

airplane, unless it has been inspected and 

modified, as applicable, in accordance with 

paragraph (g) of this AD. 

Alternative Methods of Compliance 

(AMOCs) 

(j)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), FAA, has the 

authority to approve AMOCs for this AD, if 

requested using the procedures found in 14 

CFR 39.19. In accordance with 14 CFR 39.19, 

send your request to your principal inspector 

or local Flight Standards District Office, as 

appropriate. If sending information directly 

to the manager of the ACO, send it to the 

attention of the person identified in the 

Related Information section of this AD. 

Information may be e-mailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the local flight standards district office/ 

certificate holding district office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair 

required by this AD if it is approved by the 

Boeing Commercial Airplanes Organization 

Designation Authorization (ODA) that has 

been authorized by the Manager, Seattle ACO 

to make those findings. For a repair method 

to be approved, the repair must meet the 

certification basis of the airplane. 

Related Information 

(k) For more information about this AD, 

contact Kelly McGuckin, Aerospace 

Engineer, Systems and Equipment Branch, 

ANM–130S, FAA, Seattle Aircraft 

Certification Office, 1601 Lind Avenue, SW., 

Renton, Washington 98057–3356; telephone 

(425) 917–6490; fax (425) 917–6590. 

Issued in Renton, Washington, on April 13, 

2011. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2011–9410 Filed 4–18–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–0381; Directorate 

Identifier 2010–NM–203–AD] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc. Model DHC–8–400 Series 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for the 

products listed above. This proposed 

AD results from mandatory continuing 

airworthiness information (MCAI) 

originated by an aviation authority of 

another country to identify and correct 


jdjones on DSK8KYBLC1PROD with PROPOSALS-1